The present invention relates to a mixer valve regulating unit.
A regulating unit of this kind can be used with different types of mixing valves. The provision in the regulating unit of a pressure responsive component which functions to equalize any difference in pressure that may occur between the hot and the cold water delivered to the regulating unit is a highly important criterion, since a drop in pressure will often occur in practice in one of the delivery pipes as a result, for instance, of the introduction of hot or cold water into a branch pipe connected to the water supply system. A pressure responsive component of this kind will therewith compensate for any differences in pressure that may occur and will ensure that flows of equal magnitude will be delivered to the temperature responsive part of the valve, which is necessary in order to obtain water which has the temperature to which the mixing valve has been set.
The space available in a mixing valve is limited, however, and it is therefore important that a regulating unit which is provided with a pressure equalizing or pressure balancing component has a compact construction.
Furthermore, the regulating unit should preferably have a simple and reliable construction and be capable of being readily serviced, such that the moveable components of the regulating unit can be easily removed from the mixing valve for maintenance purposes or for replacement purposes.
When dimensioning the components of the regulating unit, it must also be remembered that the mixing valve of the kind to which the present invention relates will often require the provision of one or more check valves, or non-return valves, which function to prevent water flowing from at least the hot water side to the cold water side of the system.
SE,B,7403239-2 (Publication No. 383,404) (Vargarda) describes and illustrates a mixing valve which is provided with a temperature controlling knob and which is also pressure controlled, i.e. adapted to equalize variations in pressure of the hot and cold water delivered to the valve. This mixing valve, however, lacks a thermostat part, and the quantity of water delivered is controlled by means of a handle located adjacent a temperature control knob. Consequently, it is not possible to control temperature accurately with this known mixing valve, which lacks the provision of a thermostat control.
SE,B,7409845-0 (Publication No. 406.968) (Pont-a-Mousson) describes and illustrates an insert in the mixer housing formed in a mixing tap. The insert is provided with a temperature control unit and is also intended to function as a flow control valve and has a temperature control knob located adjacent a flow control knob.
The mixing valve insert is rotationally symmetrical about its longitudinal axis and one end of the insert can be screwed into a mixing housing. The insert, however, lacks pressure equalizing means and will function unsatisfactorily in the event of pressure surges in the distribution system.
SE,B,7705979-8 (Publication No. 432,649) (Oras) describes and illustrates an equalizing device intended for mixer valves which is located upstream of the actual mixing valve, seen in the flow direction of the water, and includes a slide which forms adjustable throughflow openings for hot and cold water/respectively, said slide being moved axially in reverse directions to respective water pressures, such as to adjust the areas of the throughflow openings. The slide is connected mechanically to a thermoelement which functions to move the slide in response to water temperature, such as to control the amounts of hot and cold water delivered to the valve.
In this case, the same slide is used both for pressure compensation and temperature control. This would seem impossible to achieve successfully in practice, and in actual fact this construction is a so-called desk invented product which will never function successfully in practice. As with other known mixing valves, the mixing valve taught by this publication has the drawback that the thermostat is located in the region of the temperature control body--it is actually incorporated in the temperature control body in the construction described--which means that the thermostat part will detect a temperature other than the final mixing temperature, which impairs the properties of the mixing valve, i.e. the valve is not as effective as would be desired.